Vat dyestuffs of the pyrazine series



Patented July 12, 1938 2,123,251 VAT DYESTUFFS OF THE PYRAZINE SERIES Heinrich Neresheimer and Wilhelm Ruppel, Ludwigshafen-on-the-Rhine, and Willy Eichholz, Mannheim, Germany, assignors to General Aniline Works, Inc., New York, N. Y., a corporation of Delaware No Drawing. Application February l'i', 1937, Se-

rial No. 126,252. In Germany February 21,

10 Claims.

The present invention relates to vat dyestuffs of the pyrazine series.

We have found that valuable new vat dyestuiis are obtained by causing organic amino compounds to act on Pz-dihydroxyquinoxalines or Pz-ha1ogenhydroxyquinoxalines, the initial materials being chosen so that at least one of them is capableof being vatted.

Thedyestuffs thus obtainable correspond to the general formula /N=C-OH N: -NHR wherein R represents the radical of an aromatic compound combined in two adjacent positions with the nitrogen atoms of the pyrazino ring shown, and R an organic radical at least one of the radicals R and B being capable of being vatted. They may be, ,for example, radicals of the anthraquinone, anthrapyrimidine, dibenzanthrone, isodibenzanthrone, anthraquinonebenzacridone or anthraquinonethioxanthone series. Besides, the radical R may belong to the benzene, naphthalene, anthracene, phenanthrene' or benzanthrone series. These radicals may contain any substituents, for example alkyl groups such as methyl, ethyl or butyl groups, or halogen atoms (chlorine, bromine, or fluorine) which may also stand in a side-chain as for example radicals CF3.

For example, by-the reaction of Pz-chlor-hydroxy-1.2-pyrazinoanthraquinone ('7 .S-phthaloyl- 2.3wchlorhydroxyquinoxaline) obtainable for example by the treatment of Pz-dihydroxy-1.2- pyrazinoanthraquinone (7.8-phthaloyl-2.3-dihy droxyquinoxaline) with phosphorus oxychloride with any amino compounds there are formed vat dyestuffs giving yellow to blue dyeings, usually of Very good fastness.

Instead of 'Pz-chlorhydroxy-1.2 pyrazinoanthraquinone, Pz-dihydroxy-l.2-pyrazinoanthraquinone may be caused to react with amino compounds. It is then advantageous to add condensing agents, such as zinc chloride, boric acid, sodium bisulphate, or anhydrous copper sulphate. The dyestuffs thus obtainable usually agree with the dyestuffs prepared from Pz-chlorhydroxypyrazinoanthraquinone and the same amino compounds.

Similar dyestuifs are obtained by the reaction of Pz-dihydroxyquinoxaline or Pz-chlorhydroxyquinoxaline with amino-anthraquinones or other amino compounds capable of being vatted.

The following examples will further illustrate how the said invention may be carried out in practice but the invention is not restricted to these examples. The parts are by weight.

Example 1 A mixture of 6 parts of Pz-ch1orhydroxy-1.2- pyrazinoanthraquinone (obtainable by heating dihydroxy-l.2-pyrazinoanthraquinone with phosphorus oxychloride in the presence of nitrobenzone and forming yellow-brown needles having a melting point of 268 C.), 2 parts of aniline and 60 parts of nitrobenzene is heated to boiling for an hour. The new dyestuff thereby separates with the evolution of hydrogen chloride. It is filtered off by suction at about 100 C. and washed with nitrobenzene and alcohol. After drying it is a brown powder which crystallizes from nitrobenzene in compact red-brown needles. According to analysis it has been formed by the reaction of one molecule of Pz-chlorhydroxy-LZ- pyrazinoanthraquinone with one molecule of aniline with the splitting off of one molecule of hydrogen chloride. It dyes cotton brown-red shades having good properties as regards fastness.

When instead of aniline, other organic amino compounds are used, the reaction conditions being capable of variation within wide limits as regards temperature, the nature and amount of solvent and the duration of the reaction, correspondingly constituted dyestuffs are obtained the main properties of which are given in the following list:

acid and dyes cotton salmon shades of good fastness properties from a red vat.

No. Amino compound employed ge gg fl g ggggg Color of dyeing 1 Methylamine Orange-red needles Salmon color. 2 Ethylene diam1ne Orange-brown needles Brown-orange. 3 Ortho-toluidlne Yellow-brown needles Orange.

4 Meta-toluidlne Red-brown needles.-- Brilliant red. 5 Para-toluidine. Red-brown needles Bluish red. 6 Meta-chloranili Orange-red needles Red-orange. 7 Para-chloraniline. Red-brown needles. Orange. 8 2.4-dicl1loraniline. Yellow needles Golden yellow. 9 2.5-dichloraniline Fine red-brown nee Golden yellow. 10 3.4-dichloraniline.-. Orange needles Red-orange. 11 3.5-dlchloraniline--- Orange-brown needles Golden orange. 12 2.3.4-trichlorauiline.-- Orange leaflets Golden orange. 13 3.4.5-trichlorauiline Fine yellow needles Golden yellow. 14 2-chlor-(i-toluidine Yellow-brown leaflets Yellow. 15 Orthoanisidinm Red needles Orange. 16 Para-anisidiue Red-brown needles.-. Bluish red. 17 1-aminonaphthalene Orange needles Yellow-brown. 18 2-an1inonaphthalene Bluish red needles Orange-red. 19 l-chlor-2-aruin0napl1thalene Red needles Red-orange. 20 Para-phenylenediamine Blue-violet needles-.. Violet. 21 l-aminoanthraquinone Red-orange needles... Red-orange. 22 1 amino 4 metlioxyanthra Bluish red needles Wine-red.

quinone. 23 2-aminoantl1raquinone Orange needles Orange. 24 1 chlor 2 -aminoantl1raqui- Yellow needles. Golden yellow.

none. 25 1.4-diaminoanthraqninone Violet needles. Red-violet. 26 4.8-dian1inoanthrarufin Blue needles Blue. 27 1.5-diaminoanthraquinone. Red needles Yellow-red. 28 l-amino -4 -benzoylan1inoan Bluisll red needles Wine-red.

thraquinone. 29 1-amino-5 -benzoylaminoen Orange needles Red-orange.

thraquinone. 30 Cyelohexylamine Yellow-red needles Yellow-red. 31 S-aminoquinoline... Yellow-brown needles Yellow-brown. 32 Methylaniline Red-brown needles..- Red. 33 1 methylaminoanthraqui- Orange needles Orange none. 34 Piperidine Red-brown needles Rose. 35 Pyrazolanthrone Orange-red needles Orange-brown- Example 2 A mixture of 10 parts of Pz-dihydroxy-1.2- pyrazinoanthraquinone, 10 parts of anhydrous boric acid and 100 parts of para-chloraniline is heated to boiling for about an hour. The liquid, which was originally yellow-brown, thereby slowly becomes brown-red. If it is diluted after cooling with about 100 parts of alcohol, orangebrown needles separate out which agree in their properties and dyeing with the dyestuif obtained from Pz-chlorhydroxy 1.2-pyrazinoanthraquinone and para-chloraniline according to Example 1 (No. 7 in the list).

If instead of para-chloraniline, similar amino compounds be employed, dyestuifs are obtained which agree with those obtained from the corresponding amines in the manner described in Example 1.

Example 3 A mixture of 10 parts of Pz-dihydroxy1.2- pyrazinoanthraquinone, 10 parts of anhydrous boric acid, 35 parts of aniline and 100 parts of diphenyl ether is heated to boiling for some hours and is then diluted with alcohol while still warm to such an extent that the resulting compound crystallizes upon cooling. The dyestuff thus obtained agrees with that obtainable according to Example 1.

Example 4 A mixture of 3.2 parts of 2.3dihydroxyquinoxaline, 4.4 parts of l-aminoanthraquinone, 30 parts of phosphorus oxychloride and '75 parts of nitrobenzene is heated at 100 C. for half an hour and then boiled for about an hour. After cooling, it is diluted with alcohol. The precipitated substance is filtered off by suction, and washed with alcohol and dilute caustic soda solution. It is olive-yellow and crystallizes from nitrobenzene in orange needles. It dissolves to give the same color in concentrated sulphuric Example 5 A mixture of 10 parts of Pz-dihydroxy-L2- pyrazinoanthraquinone, 10 parts of anhydrous sodium bisulphate and. 100 parts of aniline is heated to boiling until a sample withdrawn and diluted with alcohol deposits brown crystals. The mixture is then allowed to cool, alcohol is added and the dyestufi is filtered off by suction, washed with alcohol and water and dried. It agrees with the dyestufi described in Example 1. Anhydrous copper sulphate or zinc chloride may be used instead of sodium bisulphate.

Example 6 A mixture of 3.6 parts of 2-chlor-3-hydroxyquinoxaline which forms white needles having a decomposition point of 267 C. from nitrobenzene (obtainable by heating 2.3-dihydroxyquinoxaline with phosphorus oxychloride) 5 parts of l-aminoanthraquinone and 100 parts of nitrobenzene is heated to boiling until the amount of separated dyestuff no longer increases. After cooling, it is filtered off by suction and washed with benzene. It agrees with the dyestufl' obtained in Example 4.

If Z-aminoanthraquinone be used instead of 1- aminoanthraquinone, a dyestuff is obtained which dyes cotton yellow shades from a red vat.

Example 7 A mixture of 10 parts of 3-brom-Pz-chlorhydroxy-1.2-pyrazinoanthraquinone which may be prepared in a manner similar to that described in Example 1 for the preparation of Pz-chlorhydroxy-l.2-pyrazinoanthraquinone and 10 parts of 3.5-bis-trifluormethylaniline is heated to boiling for 1 hour in 200 parts of nitrobenzene, the new dyestuff separating with an evolution of hydrogenchloride. After working up according to Example 1 it is obtained in the form of orange needles which dye cotton yellow shades of excellent fastness properties.

Dyestuifs having similar tinctorial properties are obtained by using instead of '3-brom-Pzchlorhydroxy-1.2-pyrazinoanthraquinone 3-chlor or 3-methoxy-Pz-chlorhydroxy-1.2-pyrazinoanthraquinone.

Dyestuiishaving a similar shade of 7 color results if 3.5-bis-trifiuormethylaniline be replaced by 2-ch1or-5-trifluormethylaniline or by 31-. chlor-6-trifluormethylaniline.

It is also possible to work in the following manner:

A mixture of 10 parts of Pz-chlorhydroxy-LZ- pyrazinoanthraquinone, 10 parts of 3.5-bis-trifluormethylaniline and 200 parts of nitrobenzene is heated to boiling for 1 hour, the resulting dyestuif separating with an evolution of hydrogen chloride. After working up in the manner described in Example 1, yellow needles are obtained which dye cotton yellow shades of excellent fastness properties.

If 3.5-bis-trifluormethylaniline be replaced by other amines having trifiuormethyl groups dyestuffs of a corresponding composition are obtained. The main properties of some of these when starting from the correspondingly substi tuted phthalic anhydrides, by condensation with chloror brombenzene to form the correspondingly substituted 4-halogen-aroylbenzoic acids,

' nitration in ortho-position to the halogen atom,

exchange of the halogen atom in known manner --by the amino "group, subsequent reduction of the nitro group'to theiamino group and condensation of the diamino-aroylbenzoic acid by means of oxalic acid and ring closure to the anthrae 'aquinone. "Thus the two possible isomeric Pzdihydroxypyrazinoanthraquinones having the pyrazine ring in 1.2- or 2.3-position are in general obtained which if desired may be separated from each'other forexample by the diiierent solubilities of their sulphates in moderately diluted sulphuric .acid. .By reacting with amines these two Pz-dihydroxy-pyrazino-derivatives or the P2- -halogenhydroxy compounds obtained therefrom yield dyestufis, which are ingeneral similar to those described in Example 1 or 8.

7 Example 9 A mixture of 3.1 parts of Pzch1orhy-droxy-1.2-

zinoanthraquinone or B-chloror 3-methoxy-Pzchlorhy-droxy-1.2 -pyrazinoanthraquinone: be used dyestufis having similar tinctorial properties are obtained.

Example 8 A mixture of 10 parts of Pz-dihydroxy-23- pyrazinoanthraquinone (prepared, for example, by the condensation of 2.3-diaminoanthraquinone with oxalic acid) and 100 parts of nitrobenzene is heated atfrom 180 to 190 C. and while keeping this mixture at this temperature for some hours there are added 10 parts of m-toluidine ,and .2 parts of zinc chloride. After cooling the resulting product is filtered oil by suction, washed with benzene and alcohol, whereupon any initial material which may still be present in the reaction product is removed by extraction with aqueous .piperidine. By recrystallization from nitrobenzene the dyestuff is obtained in the form of red needles. It dyes cotton red shades from agreen vat.

Similar dyestuffs may be obtained by employing Pz-dihydroxyor Pz-halogenhydroxy-LZ- or 2.3-pyrazinoanthraquinones substituted ,in one or more of the positions .5, .6, 7 and 8 of the anthraquinone nucleus, as for example .6 .or 'l-chlor-, 6- or l-methyl-, .6- or 'l-methoxy-, or 5.8-dichlor-Pz-dihydroxy or Pz-chlorhydroxy-l.2- or 2.3-pyrazinoanthraquinone. -Pyrazi'no compounds of this .type are obtainedior-example dyestuffs may be seen from the following list: pyrazmoanthraquinone, 1.7 parts of para-amino- Shade and form of the No. Amine employed crystalline dyestufi Dyeing 1 B-trifluormethylaniline Yellow-red needles Reddish orange. 2 4-trifiuormethylaniline Yellow-red laminae Golden-yellow. 3 2-cl1lor-5-trifluormethylaniline. Orange needles Golden-orange. 4 4-chlor-3-trifluormetl1ylaniline. Orange laminae. Golden-orange. 5 4-chlor-6-trifluormethylaniline. Yellow needles Greenish yellow. 6 2 melthoxy 5- trifluormethyl- Orange needles Golden-orange.

am me. 7 2 ehlor 4.5 bis trifluor- Yellow laminae .L Golden-yellow.

methylaniline. 8 2.4 dimethoxy 5 trifluop. Red needles. ,Yellow-red.

methylaniline. 9 3 trifluormethyl 4 methyl Yellow laminae -.Green1sh yellow:

sulphoaniline. 10 1.4 diam'mo 2.6 bis-trifluor- Red needles Yellowish red.

methylbenzeno. 11 2.2 diamino 4.4 bis-tri- 'Reddish yellow needles. Golden-yellow.

' fluormethyldiphenyl. l2 4 amino 3 trifluormethyl Yellow laminae Orange.

diphenyl other.

If instead of Pz-chlorhydroxy-l.2-pyraz1noandiphenyl and 30 parts of mtrobenzene is heated thraqumone 3 brom-Pz-chlorhydroxy-1.2-pyrato boiling for some time until hydrochloric acid is no longer evolved. After cooling the reaction mixture the condensation product separates in the form of red needles. It is worked up accord- :ing to Example 1, a vat dyestuff thus being obtained which dyes cotton bluish red shades from a brown vat.

Ifinstead of para-aminodiphenyl m-aminodiphenyl is used acondensation product is obtained which crystallizes in the form of red needles and dyes cotton brilliant yellow-red shades.

If 2-amino-fluorene be employed ruby-red needles are obtained which dye cotton giving an intense wine-red shade whereas the use of 4- aminofluorene leads to the formation of orange needles forming a vat dyestuff which dyes cotton brilliant red-orange shades.

1 Also when using Z-amino-diphenylene oxide as "the amine component a condensation product is obtained which forms red-brown needles and dyes cotton yellow-red shades from a brown vat.

Example 10 to boiling until the formation of the dyestufi is completed. 1 The resulting brown-red needles are 'filtered off by suction while still warm, washed with alcohol and dined.- The dyestuff which is thus obtained in a good yield dyes cotton strong red-brown shades from the vat. If the said diamino compound be replaced by other aromatic diamino compounds dyestuils having a similar composition are obtained as set forth by way of example in the following table:

marane and 30'parts of nitrobenzene is heated to boiling until hydrogen chloride no longer escapes. After cooling the reaction mixture the dye-stuff separated is obtained as described in Example 1. It forms a violet powder and dyes cotton'redviolet shades from a brown vat.

N Amino compound employed ggggsfig ggg gfig Dyeing 1 Meta-phenylenediamine Red needles Red-brown. 2 Meta-toluylenediamine Brown-violet needles. Red-brown. 3 2.5 dichlormeta phenylene Brown-red needles Orange.

diamine. 4 Para-phenylenediamine Violet needles Violet. 5 Para-toluylenediamine Blue-violet needles. Violet. 6 4.4-diaminodiphenyl. Violet needles Currant. 7 2.4-diaminodiphenyl Red needles Red-brown. 8 3.3 dimethyl 4.4 diamino Violet needles Currant.

diphenyl. 9 2.2 dimethyl 4.4 diamino Bluish red laminae.-. Bluish red.

diphenyl. 10 2.2 dichlor 3.3 dimethyl -4.4 Orange needles Orange.

diarninodiphenyl. 11 6.6 dichlor 3.3 dirnethyl -4.4' Orange laminae Orange.

diaminodiphenyl. 12 2.2-dichlor-4AdiaminodiphenyL- Carmine-red needles Orange-red. l3 3.3-dichl0r-4.4-diaminodiphenyl- Yellow-red needles. Red-brown. 14 2.2hdimethyl 6.6 diaminodi- Yellow-red laminae--. Orange.

p eny 15 4.4 dimethyl 2.2 diaminodi- Orange needles Orange.

phenyl. 16 3.3-diamino-azoxybenzene Red-brown laminae Brown-orange. 17 3.3diaminodiphenyl Brown-red needles Copper-red. 18 4.4-dian1ino-diphenyl ether Brown-violet needle Brown-red. 19 3.3-diaminodiphenyl-methane Red needles Yellow-red. 20 3.4-diaminophenylazimino-ben- Orange-brownneedles Red-orange.

zone. 21 3.4-dichlor-2-aminodiphenyl ether. Orange needles Golden-yellow.

If the diamines referred to in the above list are condensed, instead of with Pz-chlorhydroxy-L2- pyrazinoanthraquinone, with 3-brom-, 3-chloror 3 -methoxyPz-chlorhydroxy- 1.2 pyrazinoan thraquinone, dyestuffs are obtained which are similar to the corresponding dyestuifs set out in the above list as to shades of color and tinctorial properties.

Example 11 A mixture of 3.1 parts of Pz-chlorhydroxy-LZ- pyrazinoanthraquinone, 1.8 parts of Pz-cyclohexylaniline and 35 parts of nitrobenzene is heated to boiling until hydrogen chloride no longer escapes. After cooling down to room temperature the condensation product which has separated out in the form of bluish red laminae is filtered off by suction and Worked up in the usual manner. The dyestuff thus obtained dyes cotton very strong and brilliant red shades from the vat.

If, instead of para-cyclohexylaniline, employed an equal amount of meta-cyclohexylaniline be used a yellowish red dyestuff is obtained. By

When using instead of 5-aminocoumarane an equivalent amount of 2-methyl-5-aminocoumarane, 2-methyl-5-amino-'l-methoxycoumarane or 2.7 -dimethyl-5aminocoumarane dyestuffs having from red-violet to blue-violet shades are obtained; when using 2-methyl-7-aminocoumarane a product is obtained which dyes cotton strong orange shades.

Example 13 A mixture of. 3.1 parts of Pz-chlorhydroxy-12- pyrazinoanthraquinone, 1.4 parts of 3-aminoacetophenone and 30 parts of nitrobenzene is heated until the formation of the dyestuif is completed, whereupon it is worked up as described in Exple 1. An orange crystal powder is thus obtained which dyes cotton brilliant orange shades from a brown vat.

When using instead of 3-aminoacetophenone corresponding amounts of other aminoarylketones valuable dyestuffs are likewise obtained. The main characteristics of some of those dyestufi's are set out in the following list:

using ortho-cyclohexylaniline, a red vat dyestuff is formed.

Dyestuifs having similar properties are obtained by employing as amino components equivalent amounts of 5-- or 6-amino-1.2.3.4-tetrahydronaphthalene.

Example 12 A mixture of 3.1 parts of Pz-chlorhydroxy-LZ- pyrazinoanthraquinone, 1.4 parts of 5-amin0cou- If the amines referred to in the above list are reacted, instead of with Pz-chlorhydroxy-1.2-pyrazinoanthraquinone, with 3-brom-, 3-chloror B-methoxy-Pz-chlorhydroxy-1.2-pyrazinoanthraquinone, dyestuffs having similar properties are obtained.

Example 14 A mixture of 3.1 parts of Pz-chlorhydroxy-1.2- Pz-pyrazinoanthraquinone, 1.4 parts of 3-amino- 6-chlorl-pyridine and 25 parts of: nitrobenzene. is heated to boiling for ashort' time. Afterl cooling the reaction mixture is worked up as described in Example 1. Theresulting dyestuff forms redbrown needles which dye cotton reddish orange shades from a brown vat.

If instead of 3-amino-6-chlor-pyridine an equivalent amount of- 3J5-diaminopyridine be employed a yellow-brown dyestuff is obtained.

Ewample 1 5 The para-toluenesulphamino compound which may be prepared in the usualmanner from 3 amino-1.2-benzanthraquinone is nitrated and the 4-nitro-3-amino-1.2-benzanthraquinone obtained after the saponification of the nitration product is reduced to 3.4-diamino-1.2-benzanthraquinone. By heatingthelatterwith oxalic acid at C. Pzdihydroxy- 1 .2 benzo 3:4 pyrazinoanthraquinone is obtainedlinthe form ofired needles which melt above 360 C. and dissolve in sulphuric acid giving a brown coloration.

A mixture of 3 parts of the compound thus obtained, 9 parts of meta-toluidine, 0.6 part of zinc chloride and 30 parts of nitrobenzene is heated to boiling for 1 hour. The reaction mass is worked up as described in Example 8. The dyestuff thus obtained forms a dark violet powder which dyes cotton fast reddish blue shades from a brown vat.

Example 16 1.2.3.4-triaminoanthraquinone is heated with oxalic acid and the Pz-dihydroxy-l.2-pyrazinoanthraquinone4-oxamine acid formed is saponified by heating with sulphuric acid. 5 parts of the 4-amino-Pz-dihydroxy-1.2-pyrazinoanthraquinone thus obtained forming a dark violet powder which is soluble in concentrated sulphuric acid with a brown coloration, 3 parts of dehydrated boric acid and 50 parts of aniline are boiled until the formation of dyestuffs is completed. After cooling the red-violet needles separated are filtered off by suction and worked up in the usual manner. The dyestuff dissolves with difficulty in organic solvents giving a red-violet shade, readily in concentrated sulphuric acid giving a green coloration. It dyes cotton fast redviolet shades from a red-brown vat.

What we claim is:

1. A vat dyestuff of the pyrazine series corresponding to the general formula wherein R represents the radical of an aromatic compound having up to three condensed isocylic nuclei combined in two adjacent positions with the nitrogen atoms of the pyrazino ring shown, and R an organic radical, at least one of the radicals R and B being para-quinoid and capable of being vatted.

2. A vat dyestuff of the pyrazine series corresponding to the general formula wherein R represents the radical of an aromatic compound having up to three condensed isocylic nuclei combined in two adjacent positions with the nitrogen atoms of the pyrazino ring shown,

andv Rf an aromaticradical at least one of the radicals R and B being para-quin'oidand capable of being vatted.

3. A vat dyestuff of the pyrazine series corresponding to the general formula wherein R represents the radical of an anthraquinone combined in the 1- and 2-positions with the nitrogen atoms of the pyrazino ring shown, and R an aromatic radical, at least one of the radicals R and B being capable of being vatted.

5. A vat dyestuff of the pyrazine series corresponding to the general formula wherein R stands for a radical of the benzene series.

6. A vat dyestuff of the pyrazine series corresponding to the general formula wherein R stands for a radical of the benzene series containing halogen.

7. A vat dyestuff of the pyrazine series corresponding to the general formula 6 I? ham-12' 0 N wherein R. stands for a radical of the benzene series containing an alkyl group.

8. The vat dyestuff of the pyrazine series corresponding to the formula 9. The vat dyestuif of the pyrazine series corresponding to the formula EH (3113 4 N r Q II N 20 10. The vat dyestuff of the pyrazine series corresponding to the formula.

HEINRICH NERESI-IEINIER. W'ILHELM RUPPEL. WILLY EICHHOLZ. 

